The Hanover Laser Center in Germany demonstrated three future technologies in th

At OPTATEC 2022, held in Frankfurt, Germany, from October 18 to 20, the Hannover Laser Center (LZH) demonstrated three future technologies in the field of industrial optics, including: a new generation of deposition systems (Spatial ALD), micro filters, and multi radius BBMs.

Image source: Hanover Laser Center (LZH)

New generation deposition system Spatial ALD: This concept and plasma activation can achieve faster optical coating speed. This technology can evenly and efficiently coat optical conformal coatings on surfaces and optical geometric figures of various complex shapes and materials, thus supporting the manufacture of high-quality optical devices. Such characteristics make Spatial ALD system very suitable for representative fields such as automobile lighting, VR/AR, etc.

The system has four independent process chambers, which are separated by pressure and nitrogen. Each process chamber completes the ALD reaction step. The substrate is then rotated into the next chamber, thereby achieving a higher deposition rate.

As the system is based on plasma, it can operate at a low temperature below 100 ℃, making it particularly suitable for coating temperature sensitive polymer optical elements, which are usually used for displays.

It is reported that the Spatial ALD system was jointly developed by LZH and Beneq, a high-end equipment manufacturer of ALD in Finland. LZH has purchased the atomic layer deposition (ALD) system from the latter. B? Ntgen said: "Typical ALD machines are quite slow, so we are trying to make them faster, make them compatible with other ALD semiconductor processes, and adapt them to optical coating applications." "For traditional surfaces, such as spherical coating systems, it is usually preferred to accept one side or area of thicker coating, but our goal is to make the coating process uniformly transfer materials on the target shape, such as inside a sphere or cylinder."

Miniaturized filter: Whether in the field of telecommunications, quantum technology or life science, miniaturized filters have many applications. The production of thin film filters without substrates makes it possible to manufacture very small and compact optical devices, for example, for photonic integrated circuits.

Multi Radius Broadband Monitor (BBM): This monitor allows optics to be coated accurately, efficiently, and repetitively. Scientists have proposed a new concept of multi radius to improve process control. In this way, you can best follow the specified design.

In the interaction between BBM and redesign, optical elements can be coated with high accuracy, efficiency and reproducibility. The online redesign of the coating process has been validated in production. In addition to measurements in transmission, reflectance measurements on multiple measurement paths can also capture uniformity directly during the coating process.

Tammo B, Head of Coating Group, Optical Components Department, Hanover Laser Center (LZH)? Ntgen said: "Considering the micro filter based on substrate free coating materials, what we have done is to use traditional ion beam sputtering (IBS) Coating substrate. Then, we peel the coating itself from the substrate by chemical separation. Then we cut the 30-40 micron coating into 'small bricks', which can be used as optical filters between optical fiber segments in telecommunications applications. The coating material that becomes the filter is usually a combination of silicon, hafnium, tantalum and titanium oxides. "

"Inserting 'small bricks' is better and easier than trying to cover the end of optical fiber. Traditional telecom optical fiber connectors are made of coated optical fiber ends, and the loss at the connector is relatively high, so using our tiles as optical filters is more efficient. LZH is one of the few companies that can do this. Our method can achieve better quality control and mass production."

LZH is also working on another related project to deposit this coating directly on the end of the optical fiber without losing the vacuum space in the coating cavity. The challenge of this operation is to cover the end of the optical fiber, not the whole optical fiber part, in the optical fiber up to several meters long.

Tammo B? Ntgen revealed that this goal is currently an IGEL research project, proposed by LZH and its potential partners, and is expected to start in 2023. He said that this technological breakthrough can be applied not only to telecommunications, but also to endoscopy and antireflection coatings for biological imaging, such as chip inspection.

Source: OFweek